The overall objective of this research is the development of MYCIN, a computer-based system designed to use both clinical data and the judgemental knowledge of experts to improve the effectiveness of medical decision-making with regard to clinical therapeutics. Its specific goals include: a) The development of an interactive program to provide physicians with consultative advice regarding appropriate choice of antimicrobial therapy; b) development of an interactive explanation capability to permit the consultation program to explain its knowledge of infectious disease therapy and to justify specific therapeutic recommendations; c) development of a capability for computer acquisition of judgemental knowledge so as to permit experts in the field of infectious disease therapy to teach the system those therapeutic decision rules which they find useful in their clinical practice. d) implementation of the system in the clinical setting; e) evaluation of the clinical usefulness of the system and of its impact upon the clinical staff and their prescribing practices.